Producing impressions on metal plates.



UNITED STATES DATENT OFFICE.-

GHARLES N. WEST AND ALICE M. WEST, OF SAN FRANCISCO, CALIFORNIA, ASSIGNORS, BY

DIRECT AND MESNE ASSIGNMENTS, OF ONE-HALF TO WILLIAM E. DEACON OF BAKERS- FIELD, CALIFORNIA, AND ONE-FOURTH TO SAID CHARLES N. WEST AND ONE-FOURTH 'lO SAID ALICE M. WEST, OF SAN FRANCISCO, CALIFORNIA.

PRODUCING IMPRESSIONS ON METAL PLATES.

Specification of Letters Patent.

Patented March as, 1909.

To all whom it may concern:

Be it known that we, lH RLEs N. WEs'r and ALICE M. VVEsT, citizens of the United States, residing-in the city and county of San Francisco and State of California, have invented new and useful Improvements in Producing Impressions on Metal Plates, of which the following is a specification.

Our invention relates to a method of pro ducing pictorial impressions, prints -or pictures of any person or thing upon or into the surface of a metal late, by the action of light alone, and fu y developing the said picture by the same means. It consists in the method of preparing the surface of the metal plate and rendering it sensitive to the action of light, and controlling said action by a picture or other representation of the thing to be pictured or en graved upon the plate, which thing may be placed over and upon the sensitized plate so as, to be imprinted thereon, after which the plate is submitted to a chemical solution, which removes all sensitive conditions, and after thoroughly washing'with water, and being dried and varnished, a permanent picture is formed within the material of the plate.

In carrying out our process, we first cut a plate from suitable commercial sheet metal to any required size. Vi e then render its surface smooth and clean by sand blast or any other suitable method. We have found that a sand blast driven by compressed air in the ordinary manner, will render the surface of the plate smooth and chemically pure. After the plate has been pro erly repared in this manner, it is subject-e to a urther polishing process by means of a 40 brush wet with water, having soda in it to form a soda solution. l/Ve then gently brush the plate with fine emery; then wash it clean with running water, after which the plate thus pre ared is placed in an ordinary silver plating ath, and coated with silver until it possesses a pure white granulated appearance; the surface consisting of exceedingly fine crystals of silver, which seem to produce the best results in our-process. When the metal sheet has been thus plated to the desired extent, it is removed and washed well in running water, after which it is thoroughly dried. Y

We have found that a strong blast of compressed air directed u on the plate will remove all moisture, an any impurities which" may have lodged or been deposited thereon. The plate is then slightly warmed over an alcohol lamp, or by other means, and taken into a perfectly dark room, where it is subjected, first, to the vapors of any suitable hydrocarbon such as coal oil. The plate remains above the receptacle for the hydrocarbon for one or two minutes, and a portion of the insensible vapor arising from the hydrocarbon, will be deposited on the surface of the plate, which is then subjected to the vapor of iodin for from fifteen to twenty seconds of time, more or less. It is then subjected to the vapor of bromid of lime or calcium. The treatment of the plate to the action of the hydrocarbon vapor appears to render the surface of the plate more receptive to the vapors of the iodin and bromin which are afterward a plied. Experience has shown that with t 1e late thus treated, the work is facilitated. The lime having been first slaked and heated to the greatest extent by burning in a vacuum after slaking, the bromin is then added and this substance produces a certain vapor which we have called bromin of lime, over which the plate is placed, remaining subject to this vapor' from ten seconds to a minute, as ex erience and results show best. After this ast exposure, it is returned again to be subjected to the vapor of iodin, remaining as before from fifteen to twenty seconds of time. is then carried over the vapor of bromln and lime, remaining over it about the same time as described for its first subjection to this vapor. These exposures may be repeated alternately for sixor more consecutive tunes as found best by ernerience, the last exposure being preferably over the lodm, and the whole of this portion of the process is carried out in the dark, or with only such light as produced by a ruby glass or colored papers which will destroy the actnuc light ray. After the vaporizing treatment prelight, which may be known by dpractice and inclined as it enters, to allow the fluid to viously described, the plate is placed over I experience, the plate is returne to the dark room and removed from the printing frame, the face of the plate being kept downward and untouched y hand or otherwise. The plate is then placed in a pan of sufficient size and depth to hold a solution and admit the plate to be quickly lunged into it with the picture side up. he plate is sufficiently flow across the surface in a continuous wave so that it will wash and drive from the surface any remaining substance liable to leave a stain.- When thus immersed, the plate may be tipped gently from one side to the other, so that the fluid will flow back and forth over the surface until all remains of vapor or deposit upon the surface has been removed. he fluid which we have found very satisfactory for this purpose, is formed by dissolving hypo-sulfite of soda, sulfite of soda, hydrochinon and chrome-alum in water. The proportions that we have found very satisfactory are about8 ounces hyposulfite dissolved in one gallon of water, 2 ounces sulfite of soda dissolved in one quart of water, to which we add 20 drops of chemically pure sulfuric acid. 1 grain of hydrochinon and one grain of chrome alum, dissolved each in one int of water. After these are all dissolve they are poured together, well shaken and then placed in any suitable vessel for use'as above described. It will be understood that these proportions may be varied as use may suggest; the object of the solution being to destroy the sensitive condition to which the plate had previously been brought, so that ight will have no further action upon it, and the'picture will be fixed, no development being necessary further than is effected by the exposure when the picture is being made. After the late has been removed from this solution,it is thoroughly washed with water until no sensitive condition remains.

The picture may be intensified, its tones changed or improved by gently shaking or rocking it in water, to which have been added a few drops of a weak solution of chrome alum. t is then Washed, placed'in a solution of aristo-platina, or a solution of chlorid of gold. Either or both of these may be used, as in ordinary photographic methods, the plate being gently tilted back and forth in a shallow pan, the pictured side of the plate being uppermost, so that the operation can be observed. After this work is completed, the plate is Washed in running water, and may be dried in any suitable manner, preferably by a blast of compressed air of any desired pressure. This method of drying serves to greatly protect the surface of the plate from the development of stains, and to remove any impurities which may have been deposited from the Water, or from other causes. The plate may be finally varnished or lacquered, either imme diately or after a suitable lapse of time, and the process will then be complete.

It will be understood that the plates for this process may be made of any metal which can be plated or coated as herein described.

Having thus described our invention, what we claim and desire to secure by Letters Patent is- 1. The process of producing pictures and like imprints upon metal plates consisting of surfacing and cleansing said plates, coating the plates with silver, subjecting the plates successively to hydrocarbon, iodin and bromin vapors, covering the prepared plate with the negative to be imprinted and exposing to the li ht, washing the plate in a cleansing and fixing solution, and finally washing with water.

2. The process of producing pictures and like imprints upon metal plates, consisting in cleansing and surfacing said plates by means of compressed air sand blast, and subsequent brushing with water and emery, subjecting the plate to a silver plating bath,

coating the prepared plate by successive applications of vapors adapted to receive impressions, placing the sheet to be printed in juxtaposition with the prepared surface, and subjectin 'it to the action of light, removing the s eet, washing the plate in a fixing bath, then washing and cleansing the plate and coating the surface with a protecting varnish.

3. A process for producing pictures on metal plates consisting in subjecting commercial steel or iron plate to a compressed to the action of a hydrocarbon vapor and a i set our hands in presence of two subscribing sensitizing medium' applying a previously g witnesses. prepared negative 01 picture to the prepared 2 CHARLES N. WEST.

surface; subjecting the said surface to light ALICE -M. WEST. 5 sufficient to transfer the picture to the plate, Witnesses:

and then fixing and washing the plate. EDWARD L. THOMAS,

In testimony whereof we have hereunto JAMES D. SULLIVAN. 

